GF54.30-P-0009FL Attention Assist, Function
GF54.30-P-0009FL Attention Assist, Function
Attention assist, general
The attention assist function monitors the activities of the driver and recognizes fatigue or increasing inattention (e.g. on long, monotonous journeys on freeways and highways) by evaluating the driving behavior.
The attention assist function is switched on or off at the operation level in the instrument cluster (A1) and is active in a vehicle speed range of v = 80 to 180 km/h.
The attention assist function recommends taking a break if it diagnoses driver fatigue or increasing inattention.
The Attention Assist function assesses driver fatigue or increasing inattention by analyzing the steering behavior on the basis of the steering angle signal, the inherent motion of the vehicle as well as driving conditions (e.g. time of day, driving time). In the first t = 20 min of monotonous driving individual parameters and a warning threshold are determined by the driver. The instrument cluster issues a visual as well as acoustic warning message when this warning threshold has been reached. Other factors are included in the assessment in order to increase reliability.
The master control unit for the attention assist function is the Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS) or the Premium Electronic Stability Program control unit (N30/7) (with code (233) DISTRONIC PLUS).
The attention assist function is limited, however, under the following conditions:
- Sporty driving style
- Active driving situations (e.g. high cornering speed, strong acceleration, lane change)
- Poor road surface condition (e.g. surface undulations, pot holes)
- Strong crosswind
- Operation of audio equipment, telephone or other systems
The attention assist function is comprised of the following partial functions:
^ Activate attention assist function sequence
^ Function sequence for recording driving condition
^ Function sequence for evaluating driving condition
^ Output of warning message function sequence
Additional function requirements for attention assist, activate
^ Circuit 15 On
The electronic ignition lock control unit (N73) transmits the circuit 15 status to the Electronic Stability Program control unit the via the chassis CAN (CAN E).
Activate attention assist function sequence
The attention assist function must be activated in the assist menu in the instrument cluster.
Proceed as described below to do so:
- Select assist menu via the system selection button (S110s3)
- Select "Attention Asst." menu item via the scroll forward and back button (S110s1)
- Confirm selection with OK button (S110s6)
The signals of the left multifunction steering wheel button group (S110) are read in by the steering wheel electronics (N135) and transmitted via the steering LIN (LIN E1) to the steering column tube module control unit (N80). The steering column tube module control unit makes available the signals on the chassis CAN to the Electronic Stability Program control unit.
If the attention assist function is active, a coffee cup symbol (1) appears in the multifunction display (A1p13).
The selection can be changed by pressing the OK button again.
Function sequence for recording driving condition
The current driving condition is defined by the inherent motion of the vehicle. The following information is evaluated accordingly:
- Vehicle speed
- Steering movements by driver
- Vehicle longitudinal and lateral acceleration as well as yaw rate
The Electronic Stability Program control unit calculates the vehicle speed from the wheel speeds.
The wheel speeds are recorded by the following components:
- Left front axle rpm sensor (L6/1)
- Right front axle rpm sensor (L6/2)
- Left rear axle rpm sensor (L6/3)
- Right rear axle rpm sensor (L6/4)
Information about steering movements are recorded by the steering angle sensor (N49) and transmitted to the Electronic Stability Program control unit by the steering column tube module control unit via the chassis CAN.
The yaw rate, lateral and longitudinal acceleration sensor (B24/15) transmits information about vehicle longitudinal/lateral acceleration as well as yaw rate to the Electronic Stability Program control unit over the vehicle dynamics CAN (CAN-H).
Function sequence for evaluating driving condition
Depending on the different variables, the Electronic Stability Program control unit assesses the current information about the inherent motion of the vehicle.
An algorithm in the Electronic Stability Program control unit detects steering patterns which are more prevalent with increasing fatigue or inattention in the following driving conditions:
- Monotonous journey (without major longitudinal and lateral acceleration)
- No noteworthy external stimulation (e.g. surface undulations or crosswind)
The individual driver parameters to detect steering patterns are continuously adjusted. Additionally, an individual warning threshold is determined after a t = 20 minute journey. The sensitivity of the algorithm is changed depending on the driving time and time of day.
The time of day is defined by the current time, which is transmitted by the instrument cluster to the Electronic Stability Program control unit via the chassis CAN.
The received time is checked for plausibility by means o evaluating the ambient brightness
The current ambient light intensity is recorded by the rain/light sensor (B38/2). The front SAM control unit with fuse and relay module (N10/1) imports the data from the rain/light sensor over the wiper/inside rearview mirror LIN (LIN 2) and transmits this on to the Electronic Stability Program control unit via the chassis CAN. If there is a transition between dusk and dawn at an implausible time, an entry is made in the Electronic Stability Program control unit diagnostic memory
Operator intervention at one of the following components disables the detection of steering patterns:
- Radio (A2) (with code (510) Audio 20 with CD changer or with code (523) MB Audio 20 radio)
- Radio with auto pilot system (A2/56) (with code (511) Audio 50 APS with DVD changer or with code (525) MB Audio 50 APS radio)
- COMAND control unit (A40/3) (with code (512) COMAND APS with DVD changer or with code (527) COMAND APS with single DVD drive (with navigation) or with code (528) COMAND incl. DVD changer (without navigation))
- Combination switch (S4)
- Cruise control lever (S40/4)
- Steering column adjustment switch (S59) (with code (275) Memory package for electrically adjustable front seats and without code (443) steering wheel heater) or steering column adjustment switch (S59/1s1) (with code (275) Memory Package for electrically adjustable front seats and code (443) steering wheel heater)
- Left multifunction steering wheel button group or right multifunction steering wheel button group (S111)
The combination switch, cruise control lever and steering column adjustment switch signals are transmitted by the steering column tube module control unit via the chassis CAN. The multifunction steering wheel button group signals are imported via the steering LIN by the steering column tube module control unit and transmitted via the chassis CAN. The radio or COMAND controller unit signals are transmitted over the interior CAN to the front SAM control unit and from there via the chassis CAN. The Electronic Stability Program control unit receives all data via the chassis CAN.
Additional function requirements, output of warning message
^ Relevant steering pattern detected
Output of warning message function sequence
The Electronic Stability Program control unit transmits the requirement for the output of the warning message to the instrument cluster via the chassis CAN.
The prompt to take a break appears in the instrument cluster and a quadruple chime sounds twice.
An active warning can be confirmed and terminated with the OK button on the left multifunction steering wheel button group. The next warning is only possible after t > 15 minutes.
The status of the left multifunction steering wheel button group is imported via the steering LIN by the steering column tube module control unit and sent to the Electronic Stability Program control unit via the chassis CAN.
